1. Field of the Invention
The present invention relates to a superstructure of an engine. In detail, the present invention relates to a construction of an air cleaner cleaning air going to a combustion chamber of the engine, a construction of breather provided in an upper portion of a rocker arm casing, and a construction from the air cleaner and breather to an air intake part in a cylinder head.
2. Background Art
Conventionally, an air cleaner cleaning air going to a combustion chamber is provided in an upper portion or the like of an engine, and the air cleaner introduces and cleans outside air, and the cleaned air is supplied to the combustion chamber as combustion air.
With regard to the air cleaner, an air intake part is provided in a cover body which is a component member of the air cleaner so that outer air is sucked directly into the air cleaner through the air intake part. Otherwise, as disclosed in the Japanese Utility Model Laid Open Gazette Hei. 5-50061 for example, the air intake part of the air cleaner is connected to another device having an air cooling mechanism so that air cooled by the device is introduced into the air cleaner through a duct and the air intake part. Accordingly, combustion air is introduced into the engine.
However, as the above mentioned, in the case of introducing outer air directly through the air intake part provided in the air cleaner, if the engine is arranged in a closed cabinet, the heat of the engine itself may prevent the introduction of cool air. Furthermore, with regard to the above-mentioned art disclosed in the Japanese Utility Model Laid Open Gazette Hei. 5-50061, the air cooling mechanism and the air cleaner are connected to each other through the duct, whereby part number increases and the cost increases.
The air cleaner is attached to an intake port provided in a cylinder head of the engine through an intake pipe. With regard to such an air cleaner, there is an art that the air cleaner is attached to an optional position by changing the length of shape of the intake pipe and air cleaned by the air cleaner is introduced into the intake port through the intake pipe.
However, with regard to the air cleaner attached to the intake port provided in the cylinder head of the engine through the intake pipe, as disclosed in the Japanese Patent Laid Open Gazette 2001-73897 for example, the air cleaner and the intake pipe are constructed separately, whereby part number increases and the cost increases. Furthermore, the air cleaner is attached to the cylinder head through the intake pipe, therefore it is difficult to make the construction compact.
Incidentally, a breather is also provided conventionally in the upper portion of the engine that a breather chamber is provided in a rocker arm chamber covering the upper portion of the cylinder head so as to adjust pressure between the inside of the rocker arm chamber and the outside and to separate blowby gas including oil mist into a gas component and an oil component for preventing the oil mist from being discharged to the outside. The breather chamber of the breather comprises a space surrounded by the side wall of the rocker arm chamber (breather casing) and a base plate provided for a fixed interval against the reverse face of the rocker arm chamber, and oil in the blowby gas is trapped by a filter gauze or the like disposed in the breather chamber. With regard to such a breather, as disclosed in the Japanese Utility Model Laid Open Gazette Hei. 6-4311 for example, there is an art that the side wall of the breather casing and the base plate are formed integrally with each other so as to reduce part number and assemble process and to improve productivity, thereby solving the generation of noise caused by the vibration of the engine.
There is a breather provided therein with a check valve preventing pressure in the rocker arm chamber from increasing. With regard to such a breather having a check valve, gas with high pressure passes through the check valve preventing back flow and returns to the intake, port. Lubricating oil is accumulated in the breather chamber of the breather scattering in the rocker arm chamber, and when the lubricating oil is accumulated for a certain amount, the lubricating oil adheres to the vicinity of the check valve and goes out through the check valve, whereby the gas including the lubricating oil returns to the intake port. If the amount of the lubricating oil is small, the oil is not very influential. However, if the amount of the lubricating oil sucked through the inlet of the check valve increases, the lubricating oil burns in the combustion chamber so as to generate exhaust emission, thereby spoiling the exhaust. For preventing the immersion of the lubricating oil causing the exhaust emission, a baffle is provided around the air hole of the breather.
However, such a baffle forms a substantial cylindrical space with the wall surface of the rocker arm chamber, and when the breather chamber is filled with lubricating oil more than a fixed amount, the engine is slanted or vibrated in the case of mounting the engine on a vehicle so as to vibrate the surface of the accumulated lubricating oil, whereby the lubricating oil may be sucked.
On the other hand, at low temperature, such as in the winter or at a cold district, the temperature of air is low and mixed gas in the combustion chamber is not raised to the combustion temperature easily, whereby the engine may not start easily. Therefore, conventionally, with regard to a diesel engine, for raising compression ratio so as to make the mixed gas easy to burn, a passage for injecting starting adjuvant such as oil, communicated with the intake port is provided in the upper portion of the engine, and the starting adjuvant is injected through the passage so as to enter the combustion chamber through the intake port. Accordingly, the compression ratio is raised for the amount of the starting adjuvant introduced into the combustion chamber, whereby the mixed gas becomes easy to burn and the engine becomes easy to start. Such an art for improving starting ability of the engine is well known.
However, with regard to the starting adjuvant injection passage with the conventional shape, some users may introduce oil more than a fixed amount at the time of introducing the oil as the starting adjuvant. Thereupon, excessive oil enters the combustion chamber so as to cause oil hammer, whereby a connecting rod or the like may be broken. When the starting adjuvant injection passage is provided separately, the cost increases.
Therefore, with regard to the superstructure of the engine, the purpose of the present invention is to improve the attachment construction of the air cleaner that cool air can be sucked into the air cleaner in the case of arranging the engine in a closed cabinet, and to connect the air cleaner to the air cooling mechanism with a simple structure so as to reduce part number and to reduce the cost, thereby realizing a compact construction.
With regard to the breather, the purpose of the present invention is to contrive the shape of the baffle provided around the air hole (inlet) of the breather so as to prevent lubricating oil accumulated in the breather chamber from being sucked through the air hole, thereby preventing the exhaust emission caused by the lubricating oil sucked through the air hole. Furthermore, with regard to the starting adjuvant injection passage, the purpose of the present invention is to contrive the shape thereof so that even a general user can inject the starting adjuvant finely, thereby preventing overrun and oil hammer. Moreover, with regard to the breather and the starting adjuvant injection passage, the purpose of the present invention is to arrange them intensively in the upper portion of the engine so as to provide a compact superstructure of the engine.